Inverter-integrated electric compressors, which integrally incorporate inverter devices, are used as air conditioner compressors installed in electric vehicles, hybrid vehicles, and the like. This inverter-integrated electric compressor is configured so that high-voltage direct current (DC) power supplied from a power supply unit installed in a vehicle is converted to three-phase alternating current (AC) power of a required frequency by the inverter device, which is then applied to an electric motor so that the electric motor is driven.
The inverter device is configured by a plurality of high-voltage electrical components such as a coil and a capacitor configuring a filter circuit for noise removal, a plurality of semiconductor switching elements such as IGBTs configuring a switching circuit for converting electric power, a circuit board on which an inverter circuit including the filter circuit and the switching circuit, or a control circuit thereof, is mounted, and the like. The inverter device is integrated by being incorporated in an inverter housing part provided on the outer periphery of the housing of the electric compressor.
Patent Document 1 discloses an inverter device in which a control circuit board on which a capacitor or a microcomputer is mounted and an inverter circuit board on which an IGBT is mounted, or a circuit board which integrates these two circuit boards, are installed on multiple cylindrical legs in a circuit chamber provided in a housing. The inverter device is configured to dissipate heat generated by the capacitor or the microcomputer via these legs. In addition, Patent Document 2 discloses an inverter device with a configuration in which a power conversion circuit board on which switching elements, a capacitor, a coil, and the like are mounted is installed on a circuit board cover side. The circuit board cover is attached to the inverter installation surface on the housing side. A fluid member formed of a gel-like material is arranged between the switching elements, the capacitor, and the coil, and a surface opposing the installation surface side and a concave section to adjust gaps and secure heat dissipation.
Furthermore, Patent Document 3 discloses an inverter device in which, a circuit board on which switching elements, a filter coil, a capacitor, and the like are mounted, is arranged in an inner section of an inverter housing space on a circuit board supporting member such that the filter coil and the capacitor do not come into contact with the bottom wall of the housing space. A power supply connector which has metal terminals is integrally formed by resin insert molding on the side of an inverter cover which seals the housing space and the metal terminals of the power connector are connected with the circuit board side by attaching and installing the inverter cover.